Can you weld cast aluminum?
Yes, it can be welded. I'm going for machining and welded a cast aluminum case on a dirt bike motor, kind of put a hole in it when the piston broke and a piece got lodged between it and the crank. The key is getting all the oil out of the pores. The best way is to cook it in an oven at I believe it is about 500 degrees for a few hours, but I can't remember the temp for sure, but it was way up there for aluminum. Then take it out of the oven and weld it hot, then put it back in the oven and turn it down and slowly turn it off. If done right it will be stronger than before it was welded.
1970 mustang coupe restored with the help of my dad 306 on pump gas 456hp/380ft/lbs toploader, gear vendors, 5.14's